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      06-12-2014, 07:47 PM   #1
accce
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BMW Aero Kit

Is there any information on the benefits of the Aero kit. Does it create more down force? What does it change the stock drag coefficient to?

Is the Aero kit just for boy racers who drink too much BMW kool-aid?
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      06-15-2014, 06:28 PM   #2
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No one knows? Why do people buy these parts?
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      06-16-2014, 08:57 AM   #3
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Quote:
Originally Posted by accce View Post
Is there any information on the benefits of the Aero kit. Does it create more down force? What does it change the stock drag coefficient to?

Is the Aero kit just for boy racers who drink too much BMW kool-aid?
My guess is that there is probably some very minor performance benefit, but outside of a true controlled test/race environment (not just track days), the differences will not be noticeable.

Buy it for the look (if you like it), not the performace.
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      06-17-2014, 07:20 AM   #4
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Quote:
Originally Posted by accce View Post
Is there any information on the benefits of the Aero kit. Does it create more down force? What does it change the stock drag coefficient to?

Is the Aero kit just for boy racers who drink too much BMW kool-aid?
What aero kit? Have you seen an aero kit offered by BMW or are you talking aftermarket?
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      06-17-2014, 07:32 AM   #5
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Yes in the performance parts catalog. The front splitter the rear defuser the rear gurney flap.
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      06-17-2014, 08:13 AM   #6
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Well the F80/2 already has the factory spoiler, so that M Performance CF one will bring a better look a little less weight and a miniscule aerogain, however diffuser is another story and it's probably the part that would make the difference and will be included in standard equipment on a M3/4 special version (CSL, competition package or whatever it will be named).
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      07-24-2014, 01:32 AM   #7
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accce - Over the years I have gathered a lot of data as to why the OEM approach design a certain way. There is so much misinformation on the internet floating around on forums that many companies get away with false advertising. Because most of the data are classified, they are not openly shared.

For example, if a company produces a rear exit diffuser and measures the coefficient of lift and drag inside a controlled wind tunnel. That data is only an estimate. The problem with wind tunnel data is that any speed over 60mph begin to elevate the temperature of the air as it is recycled back to the front. This is referring to a full scale wind tunnel. Then you have the missing variables of real world scenarios such as turbulence from the spinning wheel and drag at the wheel well. Then there is turbulent air from cars in front of you and cross winds. Even if you were to get all of that data down.

If you change the wheels or change the height of the car even by 1", all that data you got is now inaccurate. Even the tread pattern will affect the path of air flow.

Now if you added a new front splitter, that will change the figures of the rear diffuser. Many people out there don't know that if you increase the negative pressure from the rear, it will increase the positive pressure in the front. The best practice for aerodynamic design is a balanced approach.

With the M3/M4, I assume the weight distribution is F50/R50. So adding a big GT spoiler to the rear of the car will increase the frontal lift and create a situation where the car becomes unstable at high speeds. You can feel the car get slightly understeer especially accelerating around a high speed corner. Now imagine going through the corner where the apex is cresting over a slight hill. Even your brakes will be out of balance in this situation.

So any figures a company provide is not really going to apply to you unless you kept your car at factory spec. The only figure I would pay attention to is the reduced drag coefficient, as that can help more for weekend track warriors. Unless you have power to spare, having additional downforce will not improve your track times. You are just going to make your car work harder.

I know a lot of OE has been turning to CFD but even has its limitations. In my opinion the issue is that the predicted figures never match with real world simulations. CFD is used to help designer and engineers to determine if a new approach/concept is worth investigating.

Hope this helps.
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      07-24-2014, 08:43 AM   #8
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^-- good response. Finally someone who understands just putting a big spoiler on the back of your car or a funny looking lip on the front is most likely hindering performance rather than improving.

These aftermarket companies keep naming them aero dynamic packages when they should be just calling them cosmetic packages since they are more for looks than anything.
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      07-26-2014, 12:54 AM   #9
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Quote:
Originally Posted by nsxpowered View Post
accce - Over the years I have gathered a lot of data as to why the OEM approach design a certain way. There is so much misinformation on the internet floating around on forums that many companies get away with false advertising. Because most of the data are classified, they are not openly shared.
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